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%I #12 Aug 15 2021 02:14:44
%S 1,2,185,113125,535350201,71373089217,82225037115,156231750533,
%T 268821356379
%N Numbers k that divide sigma(k) + sigma(k^2).
%C a(10) > 10^12. - _Giovanni Resta_, Jun 10 2016
%t Select[Range[150000], Mod[Plus @@ DivisorSigma[1, {#, #^2}], #] == 0 &] (* _Giovanni Resta_, Jun 10 2016 *)
%Y Cf. A000203 (sigma(n) = sum of divisors of n).
%Y Cf. A232547, A065764, A247222.
%K nonn,hard,more
%O 1,2
%A _Alex Ratushnyak_, Nov 28 2013
%E a(6)-a(9) from _Giovanni Resta_, Jun 10 2016
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